On June 5, 2025, a solo miner achieved a rare feat by mining a Bitcoin block alone, securing over $330,000 in block rewards during the highest mining difficulty ever recorded.
At block 899,826, Bitcoin’s difficulty was encoded as nBits: 0x1b38a1b5, setting a challenging target requiring miners to find a hash below a strict threshold out of more than 126 trillion possibilities. Despite temporarily boosting their hashrate to approximately 259 petahashes per second (PH/s), the miner faced roughly a 1 in 3,050 chance of success against the global network.
This miner operated through Solo CKPool, a platform allowing individual miners to attempt full block mining without sharing rewards. With fewer than 100 solo wins recorded in Solo CKPool’s history, these successes remain highly unlikely.
Bitcoin Mining Overview
Bitcoin mining involves validating transactions by forming blocks. Miners iterate over a nonce value, hashing the block header until the resulting double SHA-256 hash meets the network’s difficulty target. The first miner to achieve this adds the block to the blockchain and earns a reward in new Bitcoin plus transaction fees.
Difficulty adjusts every 2,016 blocks (around two weeks) to maintain a 10-minute block interval. When the network’s combined hashrate rises, difficulty increases; if it drops, difficulty decreases. In 2025, the network operated at record-high difficulty and over 600 exahashes per second.
Details of the Block 899,826 Win
- Confirmed: June 5, 2025, 03:48 UTC
- Transactions included: 3,680
- Total reward: ~3.151 BTC (3.125 BTC base subsidy + 0.026 BTC fees)
- USD value at confirmation: approximately $330,386
Only one mining worker was active at the time on Solo CKPool, suggesting this was a temporary setup rather than a permanent operation.
Rented Hash Power and Tactical Burst
The miner likely rented computing power from a cloud provider to reach the brief peak hashrate of 259 PH/s. This “take-a-shot” approach involves short-term hashrate spikes aimed at improving odds without long-term infrastructure investment.
Cloud mining marketplaces facilitate such rentals, enabling independent miners to target solo block rewards that carry higher risk but offer the full payout if successful.
Solo Mining Versus Pools
Mining pools distribute rewards proportional to contributed hashrate, providing steady income. Solo mining delivers all rewards to the single miner but only if a block is found, which is much riskier.
By combining rented hash power with precise timing, this miner leveraged solo mining’s potential for a rare, lucrative payout.
Implications for the Mining Landscape
Solo mining wins have also occurred earlier in 2025, demonstrating that short-term, high-capacity bursts remain a viable, though challenging, strategy against increasing difficulty. This trend highlights new opportunities for small-scale miners accessing cloud resources and suggests hybrid strategies that toggle between pooled and solo mining could emerge.
Large-scale operations continue dominating the network, but these instances prove individual miners can still influence the blockchain under record difficulty.
Conclusion
Successful solo mining under today’s harsh conditions signals a shift from pure raw computing power toward strategic, flexible approaches leveraging cloud infrastructure and timing. While the odds remain steep, such achievements encourage innovation and participation beyond industrial-scale miners.